在一个datagrid中加入两个表usig Linq C＃WPF [英] Joining two tables in one datagrid usig Linq C# WPF

问题描述

我想将两个表连接到一个数据网格中。表一： tblProjects - 表二： tblEmployeeLoginDetails

在此方法中 - private void FillProjectsDataGrid（）我想使用这个编码填充我的datagrid：

  dgViewProjects.ItemsSource = DC。 tblProjects.Where< tblProject>（c => c.ProjectID！= null）
 .Select< tblProject，ProjectData>（m => new ProjectData（）
 {
 ProjectID = m .ProjectID，
 Name = m.ProjectName，
 Status = m.ProjectStatus，
 Employee = m.EmployeeName，
}）; 
 
 dgViewProjects.ItemsSource = DC.tblEmployeeLoginDetails.Where< tblEmployeeLoginDetail>（c => c.LoginID！= null）
 .Select< tblEmployeeLoginDetail，EIDData>（m => new EIDData （）
 {
 UserID = m.LoginID，
 Name = m.EmployeeName，
 Surname = m.EmployeeSurname，
 Email = m.EmployeeEmailAddress，
 Password = m.EmployeePassword，
 Role = m.RoleID.ToString（），
 Department = m.EmployeeDepartment，
 IDNumber = m.EmployeeIDNumber，
 Gender = m.EmployeeGender ，
 Date = m.EmployeeDOB.Value，
 HomeAddress = m.EmployeeHomeAddress，
电话= m.EmployeeTelephoneNumber，
 City = m.EmployeeCity，
省= m .EmployeeProvinceCode，
 SetImage = m.EmployeeProfilePicture 
}）; 
  

对于 tblProjects ，我使用这个类：

  public struct PDData 
 {
 public string _project; 
 
 public int ProjectID {get;组; } 
 public string Name {get;组; } 
 public string Status {get;组; } 
 public string Employee {get;组; 
} 
  

对于 tblEmployeeLoginDetails 我使用这个类： / p>

  public struct EIDData 
 {
 public string _sts; 
 
 public int UserID {get;组; } 
 public string Name {get;组; } 
 public string Surname {get;组; } 
 public string Email {get;组; } 
 public string Password {get;组; } 
 public string Role {get;组; } 
 public string Department {get;组; } 
 public string IDNumber {get;组; } 
 public string Gender {get;组; } 
 public DateTime Date {get;组; } 
 public string HomeAddress {get;组; } 
 public string电话{get;组; } 
 public string City {get;组; } 
 public string省{get;组; } 
 public Binary SetImage {get;组; } 
} 
  

现在我想加入这两个表，并在一个datagrid中显示信息。我尝试了一个Linq join语句，但是我收到这个错误：

发生了一个未处理的异常类型System.InvalidCastException
在Haze.exe中

其他信息：无法投射类型
'System.Data.Linq.DataQuery 1 [Haze。 tblProject]'键入
'System.Collections.Generic.List 1 [Haze.tblProject]'。

最后这是我的连接编码：

 列表< tblProject>在DC.tblEmployeeLoginDetails中从u中加入=（List< tblProject>）
在DC.tblProjects中连接b $ u 
在u.LoginID等于b.ProjectID 
其中b.ProjectID！= null 
选择b; 
  

我不知道如何使用我必须显示的类加入这两个表一个datagrid。如果有任何建议或帮助，请随时留言。谢谢！

解决方案

这将为您提供一个新的匿名类，同时加入您的员工和项目详细信息。你拥有的加入只是为项目返回值

  var Join =（from u in DC.tblEmployeeLoginDetails 
 join b在DC.tblProjects 
 on u.LoginID等于b.ProjectID 
其中b.ProjectID！= null 
选择新的{Project = a，Employee = b}）ToList（）; 
  

然后，您必须将其绑定到您的datatable，如下所示：

  dgViewProjects.ItemsSource = Join; 
  

您的第一个代码块将覆盖第二个数据源的初始设置，而不是添加

I want to join two tables into one datagrid. table one: tblProjects - table two: tblEmployeeLoginDetails

In this method- private void FillProjectsDataGrid() I want to fill my datagrid using this coding:

            dgViewProjects.ItemsSource = DC.tblProjects.Where<tblProject>(c => c.ProjectID != null)
                .Select<tblProject, ProjectData>(m => new ProjectData()
                {
                    ProjectID = m.ProjectID,
                    Name = m.ProjectName,
                    Status = m.ProjectStatus,
                    Employee = m.EmployeeName,
                });

            dgViewProjects.ItemsSource = DC.tblEmployeeLoginDetails.Where<tblEmployeeLoginDetail>(c => c.LoginID != null)
                .Select<tblEmployeeLoginDetail, EIDData>(m => new EIDData()
                {
                    UserID = m.LoginID,
                    Name = m.EmployeeName,
                    Surname = m.EmployeeSurname,
                    Email = m.EmployeeEmailAddress,
                    Password = m.EmployeePassword,
                    Role = m.RoleID.ToString(),
                    Department = m.EmployeeDepartment,
                    IDNumber = m.EmployeeIDNumber,
                    Gender = m.EmployeeGender,
                    Date = m.EmployeeDOB.Value,
                    HomeAddress = m.EmployeeHomeAddress,
                    Telephone = m.EmployeeTelephoneNumber,
                    City = m.EmployeeCity,
                    Province = m.EmployeeProvinceCode,
                    SetImage = m.EmployeeProfilePicture
                });

For tblProjects I use this class:

public struct PDData
{
    public string _project;

    public int ProjectID { get; set; }
    public string Name { get; set; }
    public string Status { get; set; }
    public string Employee { get; set; }
}

For tblEmployeeLoginDetails I use this class:

public struct EIDData
{
    public string _sts;

    public int UserID { get; set; }
    public string Name { get; set; }
    public string Surname { get; set; }
    public string Email { get; set; }
    public string Password { get; set; }
    public string Role { get; set; }
    public string Department { get; set; }
    public string IDNumber { get; set; }
    public string Gender { get; set; }
    public DateTime Date { get; set; }
    public string HomeAddress { get; set; }
    public string Telephone { get; set; }
    public string City { get; set; }
    public string Province { get; set; }
    public Binary SetImage { get; set; }
}

Now I want to join these two tables and display the information in one datagrid. I have tried a Linq join statement but I get this error:

An unhandled exception of type 'System.InvalidCastException' occurred in Haze.exe

Additional information: Unable to cast object of type 'System.Data.Linq.DataQuery1[Haze.tblProject]' to type 'System.Collections.Generic.List1[Haze.tblProject]'.

And lastly here is my join coding:

        List<tblProject> Join = (List<tblProject>)from u in DC.tblEmployeeLoginDetails
                                                  join b in DC.tblProjects
                                                  on u.LoginID equals b.ProjectID
                                                  where b.ProjectID != null
                                                  select b;

I have no idea how to join these two tables together using the classes that I have to display it in one datagrid. If anyone has any advice or help, please don't hesitate to leave a comment. Thank you!

解决方案

This will give you a new anonymous class with both the employee and project details from your join. The join you have was only returning values for the projects

    var Join = (from u in DC.tblEmployeeLoginDetails
                                              join b in DC.tblProjects
                                              on u.LoginID equals b.ProjectID
                                              where b.ProjectID != null
                                              select new {Project=a, Employee=b}).ToList();

Then you would have to bind this to your datatable, something like this:

    dgViewProjects.ItemsSource = Join;

Your first block of code is going to overwrite the initial setting of the datasource with the second, not add to it.

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